engleski

Geomorphology of the karst plateaus in the Croatian part of the Dinaric karst (example of Slunj karst plateau)

Karst plateaus are, together with karst poljes, the biggest landforms in Dinaric karst. They are characterized by polygenetic and polyphase genesis. In the small scale karst plateaus are big flat areas with very low relative relief. Dinaric karst plateaus can stand by it self like big plateaus or can be like part of the karst-polje bottoms or they can be small tectonic fragmented and uplifted plateaus in mountainous area. In Croatian part of Dinaric karst there are three big karstic plateaus: Istrian plateau, Karlovac’s plateau (Una-Korana plateau) and North Dalmatian plateau. This large areas spread over about 4, 000 km2 witch is 7% of Croatian territory and 14% of Croatian kart area. Past researches were directed on exploration of processes and time of karts plateaus morphogenesis. There were three groups of karst plateau genesis: erosion, corrosion and abrasion theories while time of plateau genesis were assumed in range from Mesozoic to Pleistocene. This work is directed in research of morphogenesis of the surface and underground karst features in area of Slunj plateau witch is part of the extensive Karlovac’s (Una-Korana) karst plateau expanding between the Dinaric Mountainous System in the south-west and Pannonian Basin in the north-east. The researched region is elongated in the Dinaric direction, its area figures out at 336 km2, and its largest part is situated at the height of 250-400 m. The oldest rocks are the Permian sandstones, and the whole area is for the most part made of the Mesozoic platform carbonate rocks, which are in places transgressively covered with lacustrine and alluvial deposits of the Miocene, Pliocene and Quaternary age. Main structures and faults stretch in the Dinaric direction. As to exogenous processes, karst and fluviokarst ones are most significant, and fluvial, fluvio-denudational and slope processes are of somewhat less significance. In geologic past, the periods of more intensive exogenous processes were most frequent during and after orogenetic processes, and were interrupted by transgression periods. In the post Miocene period, the relief development was significantly influenced by denudation of the Neogene’s clastic sediments and a gradual exhumation of carbonate bedrock. During that process, the karst relief area increased at the expense of the fluvio-denudational relief area. It resulted in development of numerous karst forms (dolines, grikes, uvalas), but also of karstified remnants of the surface paleohydrographic network (dry and blind valleys). In those conditions numerous caves developed, where horizontal caves dominated.

karst geomorphology; karst plateau; fluviokarst; caves; speleogenesis; Croatia; Dinaric

nije evidentirano